Relative navigation and control of satellites using monocular model-based vision

A technique of navigation of formation flying satellites at geostationary altitudes using monocular model-based vision is presented. The uniqueness of this method is in that it utilizes the circular model features on the co-operative satellite in the formation. Though there are several research articles based on the point and/ or line features, no known article addresses the application of the circular features with regard to co-operative formation flying. In this paper, this novel circular feature-based technique is applied for determination of the 3-D relative position of a satellite in the formation. The Hills-Clohessey-Wiltshire (HCW) equations are employed to model the dynamics of the satellites in formation. Even though HCW equations have inherent inaccuracies, this study uses them to establish the vision algorithm. It is well known that periodic relative motions in local-vertical-localhorizontal reference frame are an in-plane ellipse and an out-of plane circle. When perturbations are included, these periodic motions cannot be maintained without control. The controlled relative motion of two spacecraft in the presence of solar radiation pressure is simulated, using the relative position information obtained from the model-based vision sensor.